1. Field of Invention
The present invention relates to medical devices. More particularly, the invention relates to a medical injection device.
2. Background
Arteries carry blood rich in oxygen and nutrients from the heart to the rest of the body. As we age, a fatty material called plaque can build up in the walls of the arteries, causing them to narrow or become blocked, which can reduce or block blood flow. This condition is known as Peripheral Artery Disease (PAD) and most commonly affects blood flow to the legs.
Early symptoms of Peripheral Artery Disease include pain, cramping, or weakness in the legs when walking or climbing stairs, which may be relieved after resting. However, as plaque continues to build on the walls of the arteries in the legs, the symptoms of PAD can become more frequent and severe. In the advanced stages of PAD, blood flow to one or both legs can become severely limited. Severely blocked arteries in the leg and sharply diminished blood flow can result in wounds that do not heal, pain in the feet or legs, infections, and even gangrene. This painful condition is known as Critical Limb lschemia (CLI), which may result in amputation.
Medical treatments including angioplasty, stents and bypass surgery may be implemented to repair blocked circulation in CLI patients' legs. A more recent medical treatment for CLI patients includes stem cell therapy. During the last several years, scientists have been studying the effects of using bone marrow cells to heal injured tissue. Bone marrow is the soft tissue within our bones. This tissue is home to unique cells commonly referred to as “adult stem cells.” Stem cells are unique in that they can become many different types of cells. Other cells in our tissues, such as muscle cells or bone cells, can only divide to produce more muscle cells or bone cells (for example, muscle cells cannot become bone cells nor can bone cells become muscle cells). However, stem cells are different. These bone marrow stem cells can leave the bone and move through the arteries to an area of tissue injury. When stem cells arrive at an injury site, they respond to signals produced by the injured tissues and divide to generate other cell types. Stem cells can produce muscle cells, bone cells, or blood vessel cells, depending on what the body needs to repair itself. This process is believed to be of central importance in the body's attempt to repair the damage caused by PAD. It is thought that delivering these cells to the diseased tissue may improve blood flow and therefore, may improve the severe symptoms of Critical limb lschemia.
In stem cell therapy, it is common to have multiple injection sites for injecting the stem cells into the patient's leg, for example, in order to build angiogenesis. To increase the volume of stem cells provided to the diseased tissue, there may be nearly one hundred needle injections about the lower leg. This is not only uncomfortable and painful for the patient, but requires an increased number of injection devices.
In view of the above, it is apparent that there exists a need for an improved medical injection device for stem cell therapy and other medical treatments.